Asthma is the most common chronic illness of childhood, but many children have poorly controlled symptoms, causing morbidities, hospitalizations, and costs. The first step toward good asthma control is accurate assessment of symptoms. Recall of the frequency and severity of symptoms is the cornerstone of asthma assessment. Unfortunately, recall by parents or young children is prone to bias and error. Symptoms are often underreported -- thus misguiding therapy. A reliable way to measure asthma symptoms over time is urgently needed to improve asthma control in young children. We propose to develop a wearable electronic device -- the Asthma gram -- to objectively assess asthma control. The Asthma gram is a small patch placed at the supra-sternal notch, straddling the 2 sternocleidomastoid (SCM) muscles. It will record and monitor respiratory sounds for up to 2 weeks. Data on symptoms of coughing, wheezing, and retractions, in relation to triggers such as exercise and cold air exposure, can then be analyzed. Our goal is to develop the Asthma gram for accurate assessment of asthma control in children to aid management, including detection of exercise-induced asthma. We have 4 specific aims. In Aim 1, we will complete the engineering development of the Asthma gram patch. The Asthma gram includes 2 accelerometers -- 1 tri-axial inertial accelerometer for movement and postural sensing, and 1 contact accelerometer for acoustic sensing -- embedded on a microelectronics platform (Eco-BT) with a real-time clock. A thermistor will be mounted to detect ambient cold air. Two force-sensing resistors over the SCM muscles will determine if wheezing episodes are associated with suprasternal retractions. In Aim 2, we will implement the user interface (UI) on smart mobile devices. There will be 4 different action modes: Nocturnal, Exercise, 24-Hour, and Before/After. In Aim 3, we will develop a cross-platform host-PC program for the Asthma gram Report. This will be a program that can import and analyze the data and generate the Asthma gram Report for clinical interpretation. In Aim 4, we will validate the Asthma gram as a clinical assessment tool. Children with asthma will be recruited (5-11 years old). We will conduct a study of 10 children admitted to the hospital ward for asthma exacerbations, to validate the wheezing and coughing detection algorithms. Once the device is fully bench tested and the algorithms validated, we will recruit 10 children for testing the 24-Hour Mode (for assessing daytime and nocturnal symptoms), and 10 children for testing the Exercise Mode (for detecting exercise-induced asthma). Participants will wear the Asthma gram for 14 days. Achieving the aims will result in a validated Asthma gram system ready for clinical trials. To accelerate commercialization following Phase I, we will (1) apply for Phase II funding for clinical trials; (2 start the process for an FDA submission; and (3) approach investors for funding.